Some rotary combine harvesters that have their engine compartments at the top, rear of the harvesters are subject to certain problems. These include belt slippage, sometimes ascribed to failure of the torque sensing unit, and engine compartment fires.
The applicant has now discovered the source of a number of these problems. It has been discovered that with the engine running, the high speed air current drawn through the engine coolant radiator by the cooling fan creates low pressure zones around the radiator, thus inducing an air flow into the openings in the engine compartment around the radiator. This may, depending on ambient conditions, create an air flow in which large amounts of dust, chaff and straw are suspended. This flow is initially into the engine compartment, but it has been found that the entire back end of the combine may be enveloped in a cloud of this particulate matter. This results in the build-up of deposits in the engine compartment and plugging of the air filter, which is in the cloud of material at the back of the combine.
When chaff and dust enter the engine compartment, a number of things can happen. The rotor or power take-off belts may slip. The torque sensing unit on the rotor drive may fail and cause the rotor belt to slip or break. Dust may build up on the hydrostatic motor, exhaust manifold, turbo charger, batteries and on the back deck of the engine compartment, creating a fire hazard. Dust may also build up behind the engine crankshaft pulley, alternator pulley and water pump pulley. Friction in those areas may heat the dust sufficiently that it begins to smolder.
The dust cloud around the back of the combine may be sufficiently thick that the air filter becomes plugged. This may in turn plug the aspirator hose to the exhaust pipe, causing a fire in the hose and burning the air filter. The burned filter will allow dust to enter the engine and cause damage to the engine.
The hydrostatic cooler in the engine and belt compartment can also plug with dust, resulting in heating problems.
The present invention proposes a solution to these problems by blocking the induced air flow around the radiator.